before i start my question i would like to say thanks to everyone who replies back its much aprectiated. now i need to grab a throtle body ive seen the lets say factory ones that are ported to 52mm or the 58mm. are these better than lets say a bbk or hollie ive seen on them that the linkages were alittle loose and i wonder if the ported factory one wont have that problem.

 

No a aftermarket TB would be your best bet for getting the most flow. Both are good brands and fitment should not be a issue. I am sure one of the senior LT1 guys will drop in and give you more info and details.

 

its pretty much the same as aftermarket, they are ported to flow more

 

You can get up to 54mm on the stock intake, if you go for the 58mm you're going to need to get the intake ported as well. That said, do you need a new TB, or are you purchasing one for a performance upgrade? You're really not going to get much, if any power out of a new TB until you have some internal work done to the car.

 

the motor that is goin in allready has internals and the intake mainifold is allready ported

 

In that case you'll probably want to go for a 58mm TB, whether that be a ported stock TB or an aftermarket one you'll probably get similar flow out of both. Depending on how much power you think you'll be making you may want to consider larger injectors (33#) as well.

 

does the motor have ported heads?

 

this is what i got and plain on doin i bought the motor out of 96 impala it was a 355 lt1 super charged. i did not by the blower with it. fortunetly for my the guy never put low compression pistons in it just had taller head gaskets. the cam is a mildly aggressive cam i got the specs some were got to look for them intake mainifold was ported to fit his 58 mm throttle body so there was no restriction. now i thought the 58mm would be to much air flow for a naturley aspirated motor so i was goin to go with the 52mm and 30# injectors

 

and i forgot to add it has trick flow heads with 1:7 rocker ratio

 

if its been opened for a 58mm then get a 58mm...30# SVO injectors should be enough